Field of the Invention
The present invention relates to a communication system, an operation control method, and a location management server. More particularly, the present invention relates to a communication system in which base stations and access gateways (AGWs) are configured in an Internet Protocol (IP) mesh network.
Related Art
In a case a base station (also referred to as a “Node B”) and an AGW as an exchange for accommodating a mobile station (also referred to as a “User Equipment” or “UE”) which is a portable telephone subscriber are configured in an IP mesh network, when the mobile station moves into an area covered by the base station, the mobile station transmits a location registration signal to the base station. The base station then selects an AGW, which is at a level above the base station, according to its own logic. For example, the base station may decide an AGW for accommodating the mobile station based on a certain bit array representing the International Mobile Subscriber Identity (IMSI) of the mobile station contained in the location registration signal.
The base station then transmits a location registration signal to the AGW selected for accommodating the mobile station and the AGW transmits a location registration signal to an Authentication, Authorization, Accounting/Home Subscriber Server (AAA/HSS) which is a location management server at a level above the AGW. In response to the location registration signal from the AGW accommodating the mobile station, the AAA/HSS makes location registration for the mobile station and manages its location (see “3GPP TR 23.882 V0.11.0 3GPP System Architecture Evolution: Report on Technical Options and Conclusions (Release 7)”, February 2006 and “3GPP TS 23.236 V6.3.0, 5.2 RNC Functions”, March 2006, for example).
A first problem is that in such a communication system with base stations and AGWs being configured in an IP mesh network, a mobile station basically continues to use an AGW to which it initially registers its location and there is no mechanism that enables users to fully enjoy flexibility of a network which allows free combination of a base station and an AGW.
A second problem is that due to lack of such a mechanism for enabling users to fully enjoy flexibility of a network which allows free combination of a base station and an AGW, the AGWs have to support every service provided by portable telephone carrier networks.